Analysis of Fluid-Solid Coupling Characteristics of Oil and Gas Submarine Span Pipelines

Abstract

In order to investigate the safe operation, dynamic characteristics and stability of oil and gas submarine pipelines, the natural characteristics of a pipe span under elastic supporting conditions were studied. The pipe was simulated as a commonly supported beam considering the interaction of not only the fluid inside and outside the pipeline but the elastic coefficients of its supporting soil as well. The differential quadrature method (DQM), an efficient numerical method to solve boundary and initial value problems, was adopted to analyze the natural characteristics of a submarine span pipeline. The differential equation and its corresponding DQM simulation equations and boundary conditions were obtained. The impacts of several factors on natural frequency of free-span submarine pipelines were studied. These factors included soil elastic coefficients at pipeline ends, span length, outer diameter, flow velocity and pressure inside pipeline, flow velocity and fluid damping outside the pipeline, density of conveying fluid, and the axially sectional force. The analytical method and numerical results presented in the paper are of value for theoretical research and engineering applications.